Cut meat into 1-inch cubes. Lightly coat a Dutch oven or large saucepan with cooking spray. Preheat over medium-high heat. Brown pork in the hot pan; drain fat.
Add the 1 1/4 cups water and the bouillon granules. Stir in the undrained tomatoes, onions, celery, oregano, cumin, garlic, and bay leaf. Bring to boiling; reduce heat. Cover and simmer 45 to 60 minutes or until pork is tender.
Stir in squash and green beans. Return to boiling; reduce heat. Simmer 5 minutes more. Combine cornstarch and the 1 tablespoon cold water. Stir into pork mixture. Cook and stir until thickened and bubbly. Cook and stir 2 minutes more. Remove bay leaf. Makes 4 servings.